1. Field of the Invention
This invention relates to a surgical tool for removing tissue from a patient. More specifically, this invention relates to a curved arthroscopic cutting device or the like.
2. Information Disclosure Statement
Until comparatively recently, most knee operations involved open surgery in order to remove growths on the patella or to remove torn cartilage from the knee joint. Such open surgery operations of necessity required a large incision thus requiring a considerable time to heal.
More recently, surgeons have been using closed surgery techniques which involve the use of an elongate rotary cutter which is inserted into a small incision of the patient adjacent the surgical site. The rotatable cutter includes an inner and an outer coaxial tube, the outer tube defining at the distal end thereof a cutter aperture or port which cooperates with a shearing blade secured to the distal end of the inner rotating tube. A source of partial vacuum is applied to the inner tube during use of the cutter in order to remove fluid and shaved particles from the surgical site.
Such closed surgery techniques have proved advantageous for a number of reasons. These advantages firstly apply to the patient undergoing such surgery because such closed surgery results in early ambulation or ability of the patient to walk after the operation. As a consequence, the patient has a shorter stay in hospital and is therefore able, to return to daily activities at an earlier date. Furthermore, by performing closed surgery, post-operative discomfort and stiffness due to the operation is substantially reduced. Finally, because closed surgery does not require an extensive longitudinal incision, scarring is kept to a minimum.
Advantages afforded to the surgeon, by such closed surgery techniques include being more readily accepted by the patient because of the reduced trauma experienced by the patient undergoing such closed surgery. Furthermore, the surgeon is able to perform a wide range of operative procedures utilizing the aforementioned arthroscopic techniques. Such operative procedures include intra-articular surgery as described hereinbefore for removing loose tissues from within the knee joint. Additionally, such procedures permit removal of pathological plica, and removal of chondromalacia of the patella. Other procedures include removal of torn meniscus or synovitis. In addition to the wide range of operative procedures that may be performed by a surgeon using such closed surgery techniques, the surgeon also experiences a reduction in the requirement for post-operative management as patients do not require sutures to be removed as is the case with open surgery.
With regard to the functioning of a hospital, the aforementioned closed surgical technique results in an increase in the possibility of treating patients requiring knee surgery as out-patients rather than requiring such a patient to occupy a hospital bed as was the case with open surgery. Therefore, viewed from the aspect of hospital management, closed surgery techniques result in an increase in revenue and a reduction in the stay of the patient in the hospital.
U.S. Pat. No. 4,203,444 to Bonnell et al discloses a surgical instrument of the aforementioned type suitable for performing closed surgery of the knee. The closed surgery technique as taught by Bonnell et al includes administering to the patient a local anesthetic followed by perforating the outer skin of the patient at selected points about the knee joint by means of trocar cannula. A liquid is introduced from a liquid source into one of the cannula to inflate the knee joint pouch. The joint is illuminated and observed by means of fibroptic probe means introduced through another cannula such that the knee joint may be visualized by the surgeon by means of close-circuit television equipment. The distal end of the arthroscopic rotary surgical cutting tool is then inserted through a further cannula and manipulated by the surgeon into the vicinity of the tissue. As the rotary blade rotates in the vicinity of the tissue to be removed, the surgeon is able to observe the removal of tissue by means of a television monitor. Furthermore, tissue formations cut or shaved away by the rotary surgical cutting tool are removed from the surgical site through the inner rotating tube of the rotary surgical cutting tool by means of a partial vacuum. Bonnell et al also describes how the surgeon manipulates the patella of the patient and manipulates the instrument backwards and forwards in order to position the cutting element at the desired angle relative to the surgical site. Bonnell et al also teaches that the direction of rotation of the blade may be reversed by suitable control means operated by the surgeon.
While the aforementioned surgical instrument has been very successful in enabling closed surgery to be preformed on patients, certain problems have been experienced by surgeons utilizing the aforementioned arthroscopic tools. One of the main problems has been that the surface of the patella to be treated is not planar. Therefore, although as disclosed in U.S. Pat. No. 4,203,444 the tool can be moved axially and back and forth, such maneuvers have presented difficulties when attempting to correctly position the cutting element relative the site to be planed. As stated in U.S. Pat. No. 4,203,444, the surgeon during the arthroscopic surgery is required to move the patella of the patient. However, the patella will only move to a limited degree thus inhibiting the surgical technique. Accordingly, there has existed in the art, the need for a cutter that could be variably positioned relative to a curved surface to be treated without the need for removing the tool and reinserting the same within a further cannula disposed angularly relative to the first cannula.
The prior art has also utilized rotary surgical cutting means in the form of a rotary burr cutting means. The rotary burr cutting means was disposed on a distal end of an inner rotating member which inner rotating member was disposed in an outer tubular member. The rotary burr cutting means functioned to smooth cut tissue during an arthroscopic surgical operation.
The present invention has as a primary objective the provision of a surgical tool that overcomes the aforementioned inadequacies of the prior art devices and provides an improvement which is a significant contribution to the advancement of the closed surgery art.
The present invention overcomes the aforementioned problem and inadequacy of the prior art device by providing a rotary surgical tool having an outer tube which may be bent during manufacture such that the cutting element may be positioned at various desired angle relative to the surface of the patella.
Another object of the present invention is the provision of a surgical tool including an inner tubular member having a flexible transmission disposed within an outer tubular member, wherein the outer tubular member may be bent during manufacture to a desired configuration.
Another object of the present invention is the provision of a surgical tool having a flexible transmission which defines a channel for removing cut tissue by means of a source of partial vacuum.
Another object of the present invention is the provision of a surgical tool having a flexible transmission which includes a spirally wound tube.
Another object of the present invention is the provision of a surgical tool having a flexible transmission interposed in an inner tubular member for transmitting rotary movement of a motor to a cutting means. The flexible transmission includes a plurality of coaxial spirals of strip material, each spiral being disposed angularly relative to an adjacent spiral such that the spirally wound tube not only mechanically transmits rotational movement of the drive motor to the cutting means, but also provides a substantially fluid tight conduit for the removal of particles of tissue removed from the surgical site.
Another object of the present invention is the provision of a surgical tool having an outer tubular member for the reception therein of an inner tubular member having a flexible transmission means. The outer tubular member is of a deformable material having sufficient mechanical strength to enable insertion of the distal end of the outer tubular member into the incision towards the surgical site.
The foregoing has outlined some of the more pertinent objects of the invention. These objects should be construed to be merely illustrative of some of the more prominent features and applications of the intended invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the disclosure. Accordingly, other objects and a fuller understanding of the invention may be had by referring to the summary of the invention and the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.